The sign accessor property of Temporal.Duration instances returns 1 if this duration is positive, -1 if negative, and 0 if zero. Because a duration never has mixed signs, the sign of a duration is determined by the sign of any of its non-zero fields.
const d1 = Temporal.Duration.from({ hours: 1, minutes: 30 });
const d2 = Temporal.Duration.from({ hours: -1, minutes: -30 });
const d3 = Temporal.Duration.from({ hours: 0 });
console.log(d1.sign); // 1
console.log(d2.sign); // -1
console.log(d3.sign); // 0
console.log(d1.abs().sign); // 1
console.log(d2.abs().sign); // 1
console.log(d3.abs().sign); // 0
console.log(d1.negated().sign); // -1
console.log(d2.negated().sign); // 1
console.log(d3.negated().sign); // 0